JP2020183643A - Reinforcement arrangement structure - Google Patents

Abstract

To provide a reinforcement arrangement structure capable of enhancing energy absorbing performance in a column beam connection part while enhancing bending proof stress.SOLUTION: A first reinforcement arrangement structure 100 mainly comprises four core reinforcing steel rods 111-114, four core pipes 121-124, and ten core confining steel 131, and is provided along the insides of a column 10 and a beam 20. The core reinforcing steel rods 111-114 extend in parallel from each other along the inside of the column 10 and the beam 20. Core confining steel 151 is attached so as to wind the core steel rods 111-114 located in the column 10 and restrict them. The core pipes 121-124 comprise four cylindrical steel pipes having an inner diameter which is identical or substantially identical to an outer diameter of the core reinforcing steel rods 111-114, for example, an inner diameter of 13 mm. In the inner circumference of the core pipes 121-124, the core reinforcing steel rods 111-114 are inserted from an opening opposing the column 10 so as to freely reciprocate. By the above, concrete is not adhered to the core reinforcing steel rods 111-114, and the core reinforcing steel rods 111-114 are not restricted by the beam 20 longitudinally.SELECTED DRAWING: Figure 1

Description

The present invention relates to a bar arrangement structure provided at a joint between a column and a beam.

Conventionally, a column-beam structure in which a plastic hinge portion is provided at the beam end, the cross-sectional area of the main bar of the plastic hinge portion is relatively small compared to the portion where the hinge does not occur, and the plastic hinge length is considerably shorter than the member length. Is known (Patent Document 1).

JP-A-2017-150179

However, in this column-beam structure, since the main bar yields at the portion where the cross-sectional area is reduced, the bending strength at the time of yielding is smaller than that when the cross-sectional area of the plastic hinge portion is not relatively small.

An object of the present invention is to provide a bar arrangement structure capable of ensuring energy absorption performance at a beam-column connection portion while ensuring bending strength.

The reinforcing bar arrangement structure according to the present invention includes a core reinforcing bar fixed to a column and a core pipe fixed to a beam, and the core reinforcing bar is inserted into the inner circumference of the core pipe.

The core pipe is preferably provided on the beam side from the joint surface between the column and the beam.

The bar arrangement structure has a hinge area provided from the joint surface between the column and the beam toward the beam side over approximately the same length as the beam, and the core pipe has a hinge area from the joint surface between the column and the beam. It is preferable to extend beyond the beam side.

The beam includes a plurality of beam main bars extending in the longitudinal direction and a beam rib bar provided straddling the plurality of beam main bars, and the plurality of beam main bars and the beam rib bar are provided in a tubular shape, and the core reinforcing bar and the beam rib are provided. The core tube is preferably provided inside the tubular shape.

The height of the bar arrangement structure in the direction of gravity is preferably 0.6 times or less the beam height of the beam.

The bar arrangement structure preferably includes a plurality of core reinforcing bars, a plurality of core tubes, and a plurality of core restraint bars provided across the plurality of core tubes.

The core pipe has a first opening that opens toward the column and into which the core reinforcing bar is inserted, and a second opening that opens at the end opposite to the first opening. It is preferable that the size of the fixing member is larger than the cross section of the core tube in a plane orthogonal to the longitudinal direction of the core tube, further including a fixing member attached to the second opening.

According to the present invention, it is possible to obtain a bar arrangement structure capable of ensuring energy absorption performance at a beam-column connection portion while ensuring bending strength.

It is a front view which shows typically the joint part of the column and the beam including the bar arrangement structure by 1st Embodiment. It is a top view which shows roughly the joint part of a column and a beam including a bar arrangement structure. It is sectional drawing of the bar arrangement structure by line III-III of FIGS. 1 and 2. It is a front view which shows typically the joint part of the column and the beam including the bar arrangement structure by 2nd Embodiment. It is sectional drawing of the bar arrangement structure by VV line of FIG. It is a front view which shows typically the joint part of the column and the beam including the bar arrangement structure by 3rd Embodiment. It is sectional drawing of the bar arrangement structure by VII-VII line of FIG.

Hereinafter, the first bar arrangement structure 100 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 3. In any of the following embodiments, the dimensions of each member are values in the 1/2 scale test body used in the structural experiment.

First, the columns 10 and beams 20 provided with the first bar arrangement structure 100 will be described. The column 10 is mainly composed of a plurality of column main bars 11 and column band bars 12, and concrete that is in close contact with the column main bars 11 and column band bars 12. The column main bars 11 extend in the vertical direction (see FIG. 1) and are arranged so as to form a rectangle in a horizontal cross section (see FIG. 2). The column band bars 12 are provided so as to surround and wind all of the plurality of column main bars 11 in the horizontal cross section, and the plurality of column band bars 12 are arranged parallel to each other in the vertical direction. As a result, the column main bar 11 and the column band bar 12 form a square tube extending in the vertical direction. The concrete forms a rectangular parallelepiped extending in the vertical direction while including the column main bar 11 and the column band bar 12.

The beam 20 is mainly composed of a beam main bar 21 composed of eight reinforcing bars D13 (SD490), a beam rib bar 29 composed of a plurality of reinforcing bars D6 (SD295A), and concrete 30 in close contact with the beam main bar 21 and the beam rib bar 29. It is composed of. The beam main bars 21 are arranged so as to form a rectangle in a cross section extending in the horizontal direction and orthogonal to the longitudinal direction. The beam ribs 29 are provided so as to surround and wind all of the plurality of beam main bars 21 in a cross section orthogonal to the longitudinal direction of the beam main bars 21, and the beam ribs 29 are provided along the longitudinal direction of the beam main bars 21. 29s are arranged in parallel. The beam main bar 21 is fixed to the column main bar 11 and / or the column band bar 12. As a result, the beam main bar 21 and the beam rib bar 29 form a square tube extending in the horizontal direction. The concrete 30 forms a rectangular parallelepiped extending in the horizontal direction while including the beam main bar 21 and the beam rib bar 29. In addition, in FIG. 2, a part of the beam main bar 21 is omitted.

The first reinforcing bar structure 100 includes four core reinforcing bars 111 to 114, four core pipes 121 to 124, ten core restraining bars 131, four fixing members 141, and one column. It is mainly provided with a restraint bar 151, and is installed from the inside of the column 10 to the inside of the beam 20.

The core reinforcing bars 111 to 114 are composed of four reinforcing bars D13 (SD490), extend parallel to each other from the inside of the column 10 to the beam 20, and have rectangular corners in a cross section orthogonal to the longitudinal direction of the core reinforcing bars 111 to 114. Placed in each part. In-column restraint bars 151 are attached so as to wind the core reinforcing bars 111 to 114 located inside the column 10, and restrain them. Further, the vicinity of the ends of the core reinforcing bars 111 to 114 located inside the column 10 is fixed to the column main bar 11 with a plate wire or the like, and is also fixed in the column 10 with concrete. The length of the core reinforcing bars 111 to 114 extending from the surface of the column 10 to the inside of the column 10 is appropriately determined according to the strength required for the first reinforcing bar structure 100. The core reinforcing bars 111 to 114 are provided inside the square cylinder formed by the beam main reinforcing bar 21 and the beam rib bar 29.

The core pipes 121 to 124 are composed of four cylindrical steel pipes having the same or substantially the same inner diameter as the outer diameter of the core reinforcing bars 111 to 114, for example, an inner diameter of 13 mm. The core pipes 121 to 124 extend from the joint surface S between the column 10 and the beam 20 to the inside of the beam 20, and are placed at the corners of the rectangle in the cross section orthogonal to the longitudinal direction of the core pipes 121 to 124. The central axes of the core tubes 121 to 124 coincide with the central axes of the core reinforcing bars 111 to 114, respectively. The length of the core pipes 121 to 124, that is, the length M extending from the joint surface S to the inside of the beam 20, is longer than the beam length L, for example, 1.2 times the beam length. That is, the core pipes 121 to 124 extend from the joint surface S between the column 10 and the beam 20 to the beam 20 side beyond the hinge region. Here, the region from the joint surface S to the same length as the beam beam L is referred to as a hinge region. Further, the length of the core pipes 121 to 124 is longer than the length of the core reinforcing bars 111 to 114 located inside the beam 20. It is provided inside the square tube formed by the core pipes 121 to 124, the beam main bar 21, and the beam rib bar 29.

The fixing member 141 is a 25 mm × 25 mm rectangular steel plate having a thickness of 3 mm. A fixing member 141 is attached to the opening end (second opening) of the core pipes 121 to 124 on the beam 20 side, for example, by welding or the like. In the plane orthogonal to the longitudinal direction of the core tubes 121 to 124, the size of the fixing member 141 is larger than the cross section of the core tubes 121 to 124. As a result, the beam-side openings of the core pipes 121 to 124 are closed, and concrete does not enter the core pipes 121 to 124 when the concrete is placed.

Core reinforcing bars 111 to 114 are freely inserted into the inner circumferences of the core pipes 121 to 124 from an opening (first opening) facing the column 10. As a result, concrete does not adhere to the core reinforcing bars 111 to 114, and the core reinforcing bars 111 to 114 are not constrained in the longitudinal direction of the beam 20. When the beam 20 is deformed with respect to the column 10, the core reinforcing bars 111 to 114 move inside the core pipes 121 to 124. Therefore, the core reinforcing bars 111 to 114 do not sufficiently increase the bending strength in the hinge region. Further, as described above, since the core pipes 121 to 124 extend from the joint surface S between the column 10 and the beam 20 to the inside of the beam 20 and do not enter the column 10, the bending strength in the hinge region is not sufficiently increased. The gap between the column-side opening of the core pipes 121 to 124 and the core reinforcing bars 111 to 114 is closed by, for example, butyl rubber or clay, and concrete does not enter the core pipes 121 to 124 when the concrete is placed.

A plurality of core restraint bars 131 are attached so as to straddle all four core tubes 121 to 124 and wind around the outer circumference. The plurality of core restraint bars 131 are composed of a plurality of reinforcing bars D4 (SD295A) and are arranged in parallel along the longitudinal direction of the core tubes 121 to 124. Here, for example, the core width W1 (see FIG. 3) is 0.5 times the beam width W2, and the core width L1 (see FIG. 3) is 0.5 times the beam width L2. The beam beam is the height of the beam 20 in the direction of gravity, and the core beam is the height of the first bar arrangement structure 100 in the direction of gravity.

Next, the function of the first bar arrangement structure 100 will be described with reference to an example in which positive and negative alternating loads are repeatedly loaded on a cantilever-type beam.

If the first bar arrangement structure 100 is not provided, when the columns 10 and beams 20 bend and yield due to loading, the concrete is peeled from the main bars and the rib bars and cracked and deteriorated. After that, when the positive and negative alternating loads are repeated, the shear deformation and slip deformation components increase as the concrete deteriorates. Due to the increase in these shear deformation and slip deformation components, the strength of the column-beam member decreases.

On the other hand, when the column 10 and the beam 20 bend and yield due to the loading, and the concrete is peeled from the main bar and the rib bar and cracked and deteriorated, if the first reinforcing bar structure 100 is provided, the core reinforcing bars 111 to 114 Absorbs the shearing force and moves inside the core tubes 121-124. As a result, the first bar arrangement structure 100 absorbs the energy due to the load, increases the shear crack strength and the bending / shear rigidity, and suppresses shear deformation and slip deformation components, so that damage to the hinge region can be suppressed.
Further, the first bar arrangement structure 100 increases the shear crack strength and bending / shear rigidity in the hinge region from the initial stage of deformation, absorbs the energy in the hinge region from the initial stage of deformation, and increases the shear force. It can be prevented.

According to this embodiment, it is possible to secure the energy absorption performance at the beam-column connection portion while ensuring the bending strength in the hinge region.

Next, the second bar arrangement structure 200 according to the second embodiment of the present invention will be described with reference to FIGS. 4 and 5. The same reference numerals are given to the same configurations as those of the first embodiment, and the description thereof will be omitted. In the second reinforcing bar structure 200, the positions of the core reinforcing bars 211 to 214 and the core pipes 221 to 224 are different from those of the first reinforcing bar arrangement structure 100.

The second reinforcing bar structure 200 includes four core reinforcing bars 211 to 214, four core pipes 221 to 224, ten core restraining bars 231 and four fixing members 141, and one column. It is mainly provided with a restraint bar 151, and is installed from the inside of the column 10 into the square tube formed by the beam main bar 21 and the beam rib bar 29.

The core reinforcing bars 211 to 214 are composed of four reinforcing bars D13 (SD490), extend parallel to each other from the inside of the column 10 to the beam 20, and have square corners in a cross section orthogonal to the longitudinal direction of the core reinforcing bars 211 to 214. Placed in each part.

The core pipes 221 to 224 are composed of four cylindrical steel pipes having the same or substantially the same inner diameter as the outer diameter of the core reinforcing bars 211 to 214, for example, an inner diameter of 13 mm. The core pipes 221 to 224 extend inside the beam 20 from the joint surface S between the column 10 and the beam 20, and are placed at the corners of a square in a cross section orthogonal to the longitudinal direction of the core pipes 221 to 224. The central axes of the core tubes 221 to 224 coincide with the central axes of the core reinforcing bars 211 to 214, respectively. Here, for example, the core width W1 is 0.5 times the beam width W2, and the core width L1 is 0.4 times the beam width L2 (see FIG. 5). Since the other configurations and the functions of the second bar arrangement structure 200 are substantially the same as those of the first bar arrangement structure 100, the description thereof will be omitted.

According to this embodiment, the same effect as that of the first embodiment is obtained.

Next, the third bar arrangement structure 300 according to the third embodiment of the present invention will be described with reference to FIGS. 6 and 7. The same reference numerals are given to the same configurations as those of the first embodiment, and the description thereof will be omitted. The third reinforcing bar structure 300 differs from the first reinforcing bar structure 100 in the configurations of the core reinforcing bars 31 to 316 and the core pipes 321 to 326.

The third reinforcing bar structure 300 includes six core reinforcing bars 31 to 316, six core pipes 321 to 226, ten core restraining bars 331, four fixing members 141, and one column. It is mainly provided with a restraint bar 151, and is installed from the inside of the column 10 into the square tube formed by the beam main bar 21 and the beam rib bar 29.

The core reinforcing bars 31 to 316 are composed of six reinforcing bars D13 (SD490), and extend parallel to each other from the inside of the column 10 to the beam 20 and have four core reinforcing bars in a cross section orthogonal to the longitudinal direction of the core reinforcing bars 31 to 314. Each is placed at the corner of the rectangle, and the other two are placed in the middle of the long sides of the rectangle. That is, the core reinforcing bar 312 is placed between the core reinforcing bar 311 and the core reinforcing bar 313, and the core reinforcing bar 315 is placed between the core reinforcing bar 314 and the core reinforcing bar 316.

The core pipes 321 to 326 are composed of four cylindrical steel pipes having the same or substantially the same inner diameter as the outer diameter of the core reinforcing bars 31 to 316, for example, an inner diameter of 13 mm. The core pipes 321 to 326 extend from the joint surface S between the column 10 and the beam 20 to the inside of the beam 20, and four of them are formed in rectangular corners in a cross section orthogonal to the longitudinal direction of the core pipes 321 to 326. Placed, the other two placed in the middle of the long side of the rectangle. That is, the core tube 322 is placed between the core tube 321 and the core tube 323, and the core tube 325 is placed between the core tube 324 and the core tube 326. The central axes of the core tubes 321 to 326 coincide with the central axes of the core reinforcing bars 31 to 316, respectively. Here, for example, the core width W1 is 0.5 times the beam width W2, and the core width L1 is 0.5 times the beam width L2 (see FIG. 7). Since the other configurations and the functions of the third bar arrangement structure 300 are substantially the same as those of the first bar arrangement structure 100, the description thereof will be omitted.

According to this embodiment, the same effect as that of the first and second embodiments is obtained.

The size of the bar arrangement structure is not limited to the above. As the cross-sectional area of the bar arrangement structure increases, the absorbed energy increases. In addition, the absorbed energy increases as the amount of reinforcing bars in the core restraining bars increases more than in the core main bars.

The ratio of the core to the beam is not limited to the above-mentioned value, but is preferably about 0.4 to about 1 / √3 times.

The beam and core may be the length in the direction in which the column 10 extends, not the height in the direction of gravity.

The columns 10, the beams 20, and the bar arrangement structures 100 to 300 do not have to have a rectangular cross section, and may have other polygonal cross sections. These internal main bars may be arranged so as to form a cylinder or a polygonal cylinder instead of a square cylinder. Further, the pillar 10 does not have to extend in the vertical direction and may be inclined with respect to the vertical direction. The beam 20 and the bar arrangement structure 100 to 300 do not have to extend in the horizontal direction and may be inclined with respect to the horizontal direction.

In any of the embodiments, the type and number of reinforcing bars are examples and are not limited to those described above, and other types and numbers may be adopted.

The fixing member 141 is not limited to a rectangular steel plate, and may be, for example, butyl rubber, clay, or the like. Further, the column restraint bar 151 may not be provided.

The size of each member shown in the present specification and the drawings is an example, and is not limited to these sizes. Moreover, the material of each member is an example and is not limited to these materials.

Although embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art will appreciate that the modifications are made in relation to the structure of each part without departing from the scope and spirit of the described invention. It is self-evident to.

10 Column 11 Column Main Rebar 12 Column Band Reinforcing Bar 20 Beam 21 Beam Main Reinforcing Bar 29 Beam Reinforcing Bar 30 Concrete 100 First Reinforcing Bar Structure 111 Core Reinforcing Bar 112 Core Reinforcing Bar 113 Core Reinforcing Bar 114 Core Reinforcing Bar 121 Core Pipe 122 Core Pipe 123 Core Pipe 124 Core Tube 131 Core restraint bar 141 Fixing member 151 In-column restraint bar 200 Second bar arrangement structure 300 Third bar arrangement structure

Claims (7)

Core reinforcing bars fixed to columns and
With a core tube fixed to the beam,
The core reinforcing bar has a reinforcing bar arrangement structure inserted into the inner circumference of the core tube. The reinforcing bar arrangement structure according to claim 1, wherein the core pipe is provided on the beam side from a joint surface between the column and the beam. It is provided with a hinge region provided from the joint surface between the column and the beam toward the beam side in a length substantially equal to that of the beam.
The bar arrangement structure according to claim 1 or 2, wherein the core pipe extends from a joint surface between the column and the beam to the beam side beyond the hinge region. The beam includes a plurality of beam main bars extending in the longitudinal direction and a beam rib bar provided straddling the plurality of beam main bars.
The plurality of beam main bars and the beam rib bars are provided in a tubular shape.
The reinforcing bar arrangement structure according to any one of claims 1 to 3, wherein the core reinforcing bar and the core tube are provided inside the tubular shape. The bar arrangement structure according to any one of claims 1 to 4, wherein the height of the bar arrangement structure with respect to the direction of gravity is 0.6 times or less the beam length of the beam. The method according to any one of claims 1 to 5, wherein the bar arrangement structure includes a plurality of the core reinforcing bars, a plurality of the core tubes, and a plurality of core restraint bars provided across the plurality of core tubes. Reinforcing structure. The core tube includes a first opening that opens toward the column and into which the core reinforcing bar is inserted, and a second opening that opens at an end opposite to the first opening.
The bar arrangement structure further includes a fixing member attached to the second opening.
The bar arrangement structure according to any one of claims 1 to 6, wherein the size of the fixing member is larger than the cross section of the core tube in a plane orthogonal to the longitudinal direction of the core tube.